• Title/Summary/Keyword: adaptive window

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An Efficient Sliding Window Algorithm Using Adaptive-Length Guard Window for Turbo Decoders

  • Lim, Hyun-Tack;Kim, Yong-Sang;Cheun, Kyung-Whoon
    • Journal of Communications and Networks
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    • v.14 no.2
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    • pp.195-198
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    • 2012
  • An efficient sliding window algorithm employing an adaptive-length guard window for turbo decoders is proposed. The proposed algorithm results in significant complexity reductions, especially for small sliding window lengths where the additional computational complexity required for the guard window is critical.

Effective Reconstruction of Stereoscopic Image Pair by using Regularized Adaptive Window Matching Algorithm

  • Ko, Jung-Hwan;Lee, Sang-Tae;Kim, Eun-Soo
    • Journal of Information Display
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    • v.5 no.4
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    • pp.31-37
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    • 2004
  • In this paper, an effective method for reconstruction of stereoscopic image pair through the regularized adaptive disparity estimation is proposed. Although the conventional adaptive disparity window matching can sharply improve the PSNR of a reconstructed stereo image, but there still exist some problems of overlapping between the matching windows and disallocation of the matching windows, because the size of the matching window tend to changes adaptively in accordance with the magnitude of the feature values. In the proposed method, the problems relating to the conventional adaptive disparity estimation scheme can be solved and the predicted stereo image can be more effectively reconstructed by regularizing the extimated disparity vector with the neighboring disparity vectors. From the experimental results, it is found that the proposed algorithm show improvements the PSNR of the reconstructed right image by about 2.36${\sim}$2.76 dB, on average, compared with that of conventional algorithms.

Effective Covariance Tracker based on Adaptive Foreground Segmentation in Tracking Window (적응적인 물체분리를 이용한 효과적인 공분산 추적기)

  • Lee, Jin-Wook;Cho, Jae-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.8
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    • pp.766-770
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    • 2010
  • In this paper, we present an effective covariance tracking algorithm based on adaptive size changing of tracking window. Recent researches have advocated the use of a covariance matrix of object image features for tracking objects instead of the conventional histogram object models used in popular algorithms. But, according to the general covariance tracking algorithm, it can not deal with the scale changes of the moving objects. The scale of the moving object often changes in various tracking environment and the tracking window(or object kernel) has to be adapted accordingly. In addition, the covariance matrix of moving objects should be adaptively updated considering of the tracking window size. We provide a solution to this problem by segmenting the moving object from the background pixels of the tracking window. Therefore, we can improve the tracking performance of the covariance tracking method. Our several simulations prove the effectiveness of the proposed method.

Ultra-fast Adaptive Frequency-controlled Hysteretic Buck Converter for Portable Devices

  • Kim, Kwang-Ho;Kong, Bai-Sun
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.5
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    • pp.615-623
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    • 2016
  • The paper describes a hysteretic buck converter including a differentiator and an adaptive hysteresis window controller. Differentiating the feedback signal achieves ultra-fast switching of the buck converter. The adaptive hysteresis window control allows a monotonous operation with predictable noise spectrum, and gives way to efficient design for variable supply and output voltages. The measurement results in a $0.13-{\mu}m$ CMOS process indicated that the switching frequency became double times higher, and the voltage ripple was reduced by up to 69%. They also indicated that the normalized switching frequency variation was reduced by 74% with variable $V_{DD}$ and by 63% with variable $V_{OUT}$. The power efficiency was improved by 3.5% depending on loading condition.

Laser Speckle Imaging Using Adaptive Windowing Method (적응 윈도우 기법을 사용한 레이저 스펙클 영상의 처리)

  • Jin, Ho-Young;Shin, Hyun-Chool
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.47 no.1
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    • pp.97-102
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    • 2010
  • A laser speckle is a random pattern that has a granular appearance produced by reflected light when a coherent laser illuminates an irregular course surface. Most important property of laser speckle is detecting micro-vascular. Speckle image needs image processing to detect micro-vascular. This paper proposes a new image processing method for laser speckle, adaptive window method that adaptively processes laser speckle images in the spatial. Conventional fixed window based LASCA has shortcoming in that it uses the same window size regardless of target areas. Inherently laser speckle contains undesired noise. Thus a large window is helpful for removing the noise but it results in low resolution of image. Otherwise a small window may detect micro vascular but it has limits in noise removal. To overcome this trade-off, we newly introduce the concept of adaptive window method to conventional laser speckle image analysis. We have compared conventional LASCA and its variants with the proposed method in terms of image quality and processing complexity.

Shape Adaptive Searching Region to Find Focused Image Points in 3D Shape Reconstruction (3차원 형체복원에 있어서 측정면에 적응적인 초점화소 탐색영역 결정기법)

  • 김현태;한문용;홍민철;차형태;한헌수
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.77-77
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    • 2000
  • The shape of small or curved object is usually reconstructed using a single camera by moving its lens position to find a sequence of the focused images. Most conventional methods have used a window with fixed shape to test the focus measure, which resulted in a deterioration of accuracy. To solve this problem, this paper proposes a new approach of using a shape adaptive window. It estimates the shape of the object at every step and applies the same shape of window to calculate the focus measure. Focus measure is based on the variance of the pixels inside the window. This paper includes the experimental results.

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An Adaptive Feedback Canceller for Fully Implantable Hearing Device Using Tympanic Membrane Installed Microphone (고막이식형 마이크로폰을 위한 이식형 인공중이 적응 피드백 제거기 구현)

  • Kim, Tae Yun;Kim, Myoung Nam;Cho, Jin-Ho
    • Journal of Korea Multimedia Society
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    • v.19 no.2
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    • pp.189-199
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    • 2016
  • Many implantable hearing aids are being developed as alternatives to conventional hearing aids which has inconveniences for use and social stigma that make hearing-impaired people avoid to wear it. Particularly, the fully-implantable middle ear hearing devices (F-IMEHD) are being actively studied for mixed or sensorineural hearing impaired people. In development of F-IMEHD, the most difficult problem is improving the performance of implantable microphone. Recently, Cho et al. have studied the tympanic membrane installed microphone which has better sensitivity and is easier to operate on patient than the microphone implanted under the skin. But, it may cause howling problem due to the feedback signal via oval window and ossicle chain from the transducer on round window in the middle ear cavity, therefore, a feedback canceller is necessary. In this paper, we designed NLMS (normalized least mean square) adaptive feedback canceller for F-IMEHD with tympanic membrane installed microphone and a transducer implemented at round window, and computer simulation was performed to verify its operation. The designed adaptive feedback canceller has a delay filter, a 64 point FIR fixed filter and a 8-tap adaptive FIR filter. Computer simulation of the feedback path is modeled by using the data obtained through human cadaver experiment.

Depth Extraction from Stereo Endoscope Using Adaptive Window (적응형 윈도우를 이용한 스테레오 내시경에서의 깊이추출 연구)

  • Hwang, D.S.;Kim, J.H.;An, J.S.;Lee, S.J.;Lee, M.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.265-266
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    • 1998
  • This paper describes a depth extraction algorithm in the stereo endoscopic images using adaptive window. First, The relation between the 3D coordinates in the world and the 2D coordinates in the image plane is estimated using camera calibration. Next, stereo matching is performed to find the conjugate pairs in the left and right images. To improve the precision of the matching result, adaptive window which can be varied on the shape as well as on the size according to the area characteristics is used. Finally, the result from the stereo matching and that of camera modeling are combined to extract the real depth information.

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A Study on Adaptive Stereo Matching for DEM Generation (DEM 제작을 위한 Adaptive Stereo Matching 에 관한 연구)

  • 김정기;김정호;엄기문;이쾌희
    • Korean Journal of Remote Sensing
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    • v.8 no.1
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    • pp.15-26
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    • 1992
  • This paper describes an implementation of adaptive stereo matching for DBM generation. The matching method of two stereo satellite images to find corresponding points used in this paper is area-based matching, which is usually used in the field of making DBM. Same window size and search area used as in the conventional matching methods and we propose adaptive stereo matching algorithm in this paper. We cluster three areas which are consist of mountainous areas, cultivated areas and cities, and rivers and lakes by using proposed linear feature extracting method. These classified areas are matched by adaptive window size and search area, but rivers and lakes is excluded in this experiment. The matching time is three times faster than conventional methods.

Tree Removal Filtering using Aerial Photographs DTM to Analyze Producing Section of Forest Soil Sediment Disaster (산지토사재해 발생구간 분석을 위한 항공사진 DTM에서의 수목필터링)

  • Woo, Choong-Shik;Youn, Ho-Joong;Jeong, Yong-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.10 no.3
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    • pp.22-30
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    • 2007
  • It is difficult to generate DTM using aerial photographs because trees usually cover disaster occurred areas. So, this study proposed how to filter by moving window using digital aerial photographs and generate accurate DTM. The results were compared with those of adaptive filtering by commercial digital photogrammetry software (Socet set) to find out the effect of tree removal by window size in forest soil sediment disaster. And then they were compared with DTM generated from LiDAR data. As a result, it was showed that the accuracy of moving filtering DTM was lower than that of LiDAR DTM while it was higher by 6m than that of Adaptive filtering.

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